SML: 1 more exhaust question

[DOG1132]

This might sound like a stupid question but i am a rookie to the performance 
side of cars,but somebody i know said he hollowed out his catalyc converter 
and swears that he gained power and a little deeper growl from his 94 
jetta.So is he full of it or what?If you get a aftermarket cat. or hollowed 
yours out is there any power gain or just a deeper growl?
                                   thanx,
                                   chris 94 se-xe w/heavy ass 16's that still 
smokes a 94 jetta
                                    lol